8 Unforgettable Lessons from the American Freethought Movement to Revive Your Intellectual Independence

Showtime. It’s 1879, and the hall in New York is packed well past legal capacity. People are sitting in the aisles, propping themselves against the back wall, leaning in because they don’t want to miss a syllable. The man gripping the lectern is tall, with a voice that lands like a friendly check. His name is Robert Ingersoll, and he has just announced the title of his lecture: Some Mistakes of Moses.

He proceeds to call the Bible “a book of mistakes.” He jokes about the whale, laughs at the arithmetic of Noah’s flood, and pans the Garden of Eden as a “splendid failure.” And the audience? They’re delighted. The men in their stiff collars are roaring. The women behind their fans are grinning into their gloves. Many of these same people will stumble home, climb into bed, and say their prayers next to a Bible they honestly can’t unread now.

How did a self-taught lawyer from Illinois become the most sought-after stage performer in America—without singing, dancing, or containing a single note of conventional piety? Because he did something scandalous for the era. He asked people to think.

Now it’s your turn. Somewhere between your phone’s notifications and the hot take in your feed, the old American muscle of freethought has atrophied. We still live in the world those freethinkers built, but we’ve forgotten the weight room. This piece is the repair manual. It’s not history for its own sake—it’s eight lessons from the wild, messy, hilarious freethought movement, and each one comes with a habit you can start practicing this afternoon.

Here’s the kicker. You don’t have to be an atheist to use any of it. The freethought movement was never really about God. It was about the source code of conviction—where your beliefs come from and whether you’ve ever actually vetted them. So, let’s dig in.

1. The Source of the Message Matters More Than the Message

Back in 1785, the Revolutionary War was barely settled and a guy named Ethan Allen—yes, the Green Mountain Boys guy—published a book so dangerous that most of its first run was quietly destroyed by a fire. The book was Reason the Only Oracle of Man, and Allen wrote it for a blunt reason: ordinary veterans had just bled to die in a war against one earthly king, only to find themselves still bowing to a celestial one. Allen’s claim was preposterous for his time. He said the contents of the Bible should be tested by reason, not the other way around. You didn’t start with scripture and squeeze your brain around it. You started with evidence and experience, and saw what survived.

A few years later, Thomas Paine performed the same trick in two languages. Common Sense told Americans to doubt monarchy; The Age of Reason told them to doubt revelation. Same principle. Before you debate whether a claim is true, ask what made you consider it in the first place.

Modern habit you can steal: Check the plumbing before you drink the water. If you learned a “fact” from a meme, a televangelist, a TikTok science hack, or a partisan newsletter, do not argue with the conclusion. Go upstream. Who printed it? Who funds the platform that amplified it? If the source’s entire purpose is your assent, treat the message like a sales pitch and not a report.

Do the unpleasant thing. Read one story from the source you’re anti, and read one from the side you’re for. Freethought begins the moment you notice your own automatic allegiance.

2. Applause Is Not the Same as Evidence

Fast-forward to Ingersoll’s peak. He’s on stage three hundred nights a year, an endless railroad schedule of one-night stands from Brooklyn to Denver. The newspapers call him “The Great Agnostic,” and in a Protestant nation that’s meant as an insult. It wasn’t landing. By the 1890s his lectures had reportedly earned well over a million dollars in ticket revenue—a fortune in any era—and the whole of it flowed from one man’s regular habit of telling people, quite cheerfully, I do not know.

Sounds like a recipe for obscurity, right? It was the opposite. He outdrew revivalists. Why? Because the freethought movement had tapped into something lasting: the pleasure and the dignity of making up your own mind, in public, at your own risk. His career is the real-world proof that intellectual independence isn’t a niche market. It never was.

But there’s a harder lesson under the applause. Ingersoll was also a fierce Republican who delivered the most famous political speech of his era, and he was just as prone to party loyalty as the rest of us. Here’s the wince: he kept faith in some political bromides he never fully investigated, and he claimed enormous cosmic certainty about things like hell—heaven, that is—he claimed enormous certainty that they don’t exist. In other words, the man could out-skeptic a parish priest but still glaze over when it came to his own tribe.

Modern habit you can steal: Separate the theater of independence from its practice. It’s easy to feel brave by doubting your neighbor’s God. It’s far harder to doubt the candidate, the cause, or the philosophy that makes you popular at dinner. So this week, select your most comfortable belief and subject it to the same ruthless cross-examination you’d give a stranger’s. Pace the floor while you do it. It’s legal. Nobody has to know.

3. Morality Survives Without a Cosmic Cop

The loudest fear of the religious establishment, back then and now, runs like this: if you take away hell, nobody will behave. The American freethought movement met that claim head-on. No one embodied it better than Frances Wright, a Scottish-born reformer who arrived in the U.S. in the 1820s and proceeded to lecture on slavery, public education, women’s rights and religious superstition—often to packed houses that booed her simply for being a woman speaking aloud about ideas. The press called her the “Red Harlot of Infidelity.”

Her friend Ernestine Rose, a Jewish immigrant from Poland, did even more. Rose spent decades on the platform fighting for a married woman’s right to own property, and she worked side-by-side with suffragists like Susan B. Anthony and Elizabeth Cady Stanton. Rose was a fearless materialist. She told audiences that human kindness, not angelic policing, was the only foundation a decent society needed. Let’s unpack that claim, because it’s genuinely radical: she believed that free people, reasoning about the consequences of their actions, could build a more just world than people acting out of fear of damnation.

Modern habit you can steal: Test your ethics against outcomes, not just authority. When you’re deciding what to do, skip the part where you ask, What will people think? and get straight to What will this do to the other human? That’s the whole game.

You don’t have to believe in naturalism to build this habit. You just have to practice the counterintuitive move of helping people because they’re people, full stop. No points in heaven. No karma ledger. Try one anonymous act of useful kindness this week and watch how quietly it changes your posture toward the world.

4. Discomfort Is Not Truth, But It’s a Traffic Signal

Let’s drop into the lower depths of the movement. D.M. Bennett was a Civil War-era skeptic who founded a weekly paper called The Truth Seeker in 1873. The paper was everything: philosophy, science, humor, scandal, and open warfare against the moral policing of the day. In 1877, Bennett published a pamphlet-turned-open-letter to Jesus Christ. It was audacious, mocking and theologically disrespect